Fluid system with valve actuated pump motor switch



Jan. 11, 1966 SCHMIEL ETAL 3,228,193

FLUID SYSTEM WITH VALVE ACTUATED PUMP MOTOR SWITCH Filed Nov. 5, 1963 wll:

I IIIIIIIII 4 INVENTORS HERBERT H. BOHMIEL and LOUIS G. HAJMA ATTORNEYSUnited States Patent O 3,228,193 FLUID SYSTEM WITH VALVE ACTUATED PUMPMOTOR SWITQH Herbert H. Schmiel, Trailard Drive, Willoughby, Ohio, andLouis G. Hajma, 24800 Emery Road, Warrensville Heights, Ohio Filed Nov.5, 1963, Ser. No. 321,611 Claims. (Cl. 6052) The present inventionrelates generally as indicated to a fluid system with a valve actuatedpump motor switch and more particularly to a novel switch arrangementwhich energizes the electric drive motor for the system pump wheneverthe directional control valve of the system is shifted to an operatingposition whereat fluid under pressure delivered by the pump is conductedto a fluid motor.

It is a principal object of this invention to provide a fluid system inwhich the electric switch that controls energization and deenergizationof the pump drive motor is attached on the directional control valve ofthe system for operation of the switch plunger by the movable valveelement of the directional control valve.

It is another object of this invention to provide a combinationdirectional control valve and electric switch so arranged that theswitch contacts are closedto energize the pump drive motor while thepump outlet is yet in communication with the tank bypass passage of thevalve whereby the motor is started under substantially no load.

It is another object of this invention to provide a directional controlvalve and switch arrangement as aforesaid in which the switch isadjustably mounted on a fixed part of the directional control valvehousing so that initially the contact elements of the switch are in Offposit-ion when the movable valve element of the directional controlvalve is in neutral position.

It is another object of this invention to provide a motor startingswitch of the character indicated which has its movable cont actor andcontacts enclosed therewithin and thus protected from fouling and arcingby foreign matter as may be encountered, for example, in conjunctionwith fluid systems employed in fork lift trucks and like materialhandling equipment.

It is another object of this invention to provide an electric switch ofthe character indicated which is provided with a transparent cover whichprovides a clear view of the contacts and contactor therewithin, thus tofacilitate adjustable mounting of the switch on a directional controlvalve.

Other objects and advantages of the present invention will becomeapparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention,then comprises the features hereinafter fully described and particularlypointed out in the claims, the following description and the annexeddrawing setting forth in detail a certain illustrative embodiment of theinvention, this being indicative, however, of but one of the variousways in which the principle of the invention may be employed.

In said annexed drawing:

FIG. 1 is a cross-section view of a typical spool-type directionalcontrol valve having a pump motor energizing switch connected theretofor engagement of the switch plunger by the valve spool, the remainingelements of the fluid and electrical system, namely, the tank, the fluidmotor, the pump, the pump drive motor, the motor starting relay, and thepower transformer, being shown schematically;

FIG. 2 is a cross-section view taken substantially along the line 2-2,FIG. 1; and

ice

FIG. 3 is a cross-section view taken substantially along the line 33,FIG. 1.

Referring now more particularly to the drawing, and first to FIG. 1, thefluid system herein comprises a directional control valve 1, a pump 2, adouble acting fluid motor 3 and a tank 4.

Insofar as the directional control valve is concerned, it may be of thespool type, as shown, the housing 5 thereof having a bore 6 therethroughwhich, starting at the middle, is intersected by a bypass passage 7which leads to the tank port 8; by a pair of bypass branch passages 9; 9straddling the .bypass passage 7 and communicating with the inlet port10; by a pair of pressure feed passages 11; 11 also leading to the inletport 10 and communicating with the aforesaid bypass branches 9; 9 by apair of motor passages 12; 12 adapted to be communicated via conduits14; 14 with the ports of the fluid motor 3; and by a pair of returnpassages 15; 15 which lead to the tank port 8. The directional controlvalve 1 will preferably have therein a pressure relief valve 16 whichopens communication between the inlet port 10 and one return passage 15in the event that the fluid pressure in said inlet port 10 builds up toa value exceeding that for which the relief valve 16 is set. Conduits17, 18, and 19 respectively communicate the discharge port of pump 2with inlet port Ill, the intake port of pump 2 with tank 4, and the tankport 8 with tank 4.

Reciprocable in said bore 6 is the valve spool 20 which has alternatelands and grooves and is yieldably held in the neutral position as shownby the centering spring mechanism 21 contained within the cap 23 whichis screwed onto said housing 5.

When the spool 20 is in neutral position the inlet port 10 and tank port8 are in fluid communication with each other through the aforesaidbypass branch passages 9; 9 and bypass passage 7, and communicationbetween the respective feed passages 11; 11 and motor port passages 12;12 blocked.

When the spool 20 is shifted to the right, as viewed in FIG.. 1, thepump drive motor 25 is started (-as hereinafter explained) during theinitial portion of the movement of the spool 20, the fluid delivered bythe pump 2 being freely circulate-d back to the tank 4 through theaforesaid bypass passages 9 and 7, whereby the motor 25 is started undersubstantially no load. As the spool 20 approaches its normal operatingposition, spool land 26 closes communication between one bypass branch 9and bypass passage 7 and the metering section 27 of land 28 graduallycloses communication between the other bypass branch 9 and bypasspassage 7. Also, communication is gradually opened between the left feedpassage 11 and leftmotor passage 12 by the metering section 29 of land23 so that fluid under pressure will be delivered to the head end of thefluid motor 3 via the conduit 14 and the fluid displaced from the rodend of the motor 3 will flow through the conduit 14 to the right motorpassage 12 to the adjacent return passage 15. When the manual force onthe left end of spool 20 is released, the spring 30 will, through thefollower 31., return the spool 20 to its neutral posit-ion at which timethe switch 32 opens to deenergize the pump drive motor 25.

When the spool 20 is shifted to the left from its neutral position, theswitch 32 will again close to energize the motor 25 before the aforesaidbypass 97 is closed and continued movement of the spool toward the leftwill open communication between the right feed passage 11 and rightmotor passage 12 to conduct fluid under pressure through the conduit 14into the rod end of the fluid mot-or 3 and the fluid displaced from thehead end of the motor 3 will flow through the conduit 14 and through theleft motor passage 12 to the adjacent return a: passage 15. The rightland 28 with its metering sections 27 and 29 operate as previouslydescribed to provide for gradual cut-ofi and cut-in of the bypass andpressure circuits. As previously described, when force on the spool 20is released, the spring 30 will, through the follower 34, return thespool to its neutral position again opening the switch 32 fordeenergizing the pump drive motor 25.

Referring now in detail to the switch 32, it comprises a plastic body 40having a fixed jaw 41 and a movable jaw 42 by which it is securely andadjustably clamped on the cylindrical end portion 43 of the cap 23,clamping being effected by tightening the screws 45 which draw themovable jaw 42 toward the fixed jaw.

Secured in the body 40 as by means of the respective pairs of screws 46and 47 are two pairs of spaced contact elements 48 and 49 of which theelements 49 have integral external terminals 50. Terminal elements 57are secured by the screws 46 to elements 48. Reciprocable in the body 40is a switch plunger 52 which is urged by the springs 53 toward the leftso that the plunger head 54 presses the contactor 56 against the leftset of contacts 48 to establish a circuit through the coil 57 of therelay contactor 58 for the motor 25. When the plunger 52 is moved to theright, the spring 59 urges the contactor 56 against the right set ofcontacts 49 as the head 54 of the the plunger continues to move to theright hereafter, the coil 57 again being energized to start the motor 25as aforesaid.

To seal the interior of the switch body 40, a packing ring 60 thereinhas a sliding seal around plunger 52 and preferably the internal hexsize in the cap 23 is smaller than the outside diameter of the packingring 60 so that the latter cannot inadvertently drop out.

Mounted on the body 40 as by means of the screws 61, is a transparentcover plate 62 which has laterally extending ribs adjacent its peripherywhich overlap portions of the body 40 and terminals 50 so as to closethe interior of the body 40 from foreign matter. The transparent cover62 is also useful in adjustably mounting the switch 32 on thedirectional control valve 1 since all that it is necessary to do is toplace the socket or recess 63 defined by the fixed jaw 41 and themovable jaw 42 over the reduced end portion 43 of the cap 23, then movethe switch 32 to the left as viewed in FIG. 1, until the contactor 56 ismid way between the pairs of contacts 48 and 49. With the switch 32 inthat position, the screws 45 will be tightened to draw the movable jaw42 toward the fixed jaw 41 and thus securely clamp the switch 32 on thedirectional control valve 1. By way of example, the directional controlvalve spool 20 may have .22 travel in opposite directions from theneutral position to its respective operating positions, whereas thespace between the contactor 56 and the respective sets of contacts 48and 49 is only, say, .040", whereby the switch 32 will be closed toenergize the motor 25 after only .040 movement of the spool 21 in eitherdirection, whereby the motor 25 starts the pump 2 without substantialback pressure since the bypass passages 9 and 7 will yet besubstantially fully open. Continued movement of the spool 20 theremainder of its stroke will then progressively cut off the bypass andopen up communication between the selected adjacent pressure feed andmotor passages 11 and 12.

In FIG. 1 the power line for operating the motor is designated as L1, L2and the switch 32 and relay coil 57 are preferably in the low voltagecircuit of transformer 64. Of course, when the circuit of the relay coil57 is closed, the relay contactor 58 will .be actuated thereby to closethe motor 25 circuit to drive the pump 2.

It is to be understood that the present invention may be employed insystems wherein two or more directional control valves are employed forcontrolling the actuation of a corresponding number of fluid motors, andeach spool may have associated therewith a switch 32 of the characterherein described so as .to start the pump drive motor whenever any oneof the spools is actuated. As evident, the nested springs 53 applygreater force on the plunger 52 than does the contactor spring 59 and,likewise, when the switch 32 is in its Ofi position as shown, the netspring force on the switch plunger 52 will be less than the force of thecentering spring 30 holding the spool 20 in its neutral position.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims, or the equivalent ofsuch, be employed.

We therefore particularly point out and distinctly claim as ourinvention:

1. In combination, a directional control valve comprising a housinghaving an inlet port for connection with a pump, a tank port forconnection with a tank, and at least one motor port for connection witha fluid motor, said housing also having a bore therethrough intersectedaxially therealong by a bypass passage from said inlet port to said tankport, and a pressure feed passage from said inlet port to said motorport; a valve spool movable axially in said bore from an inactive springield position whereat said inlet and tank ports are in fluidcommunication via said bypass passage and communication between saidinlet and motor ports via said feed passage is blocked by said spool, toan operating position whereat said spool closes said bypass passage andfluid communication is established thereby between said inlet and motorports via said feed passage whereby said fluid motor is actuated byfluid under pressure in said inlet port conducted to the motor throughsaid motor port; and electric switch means for energizing an electricdrive motor for said pump; said switch means comprising a body securedto said housing, a switch plunger means disposed adjacent an end of saidspool, a cont-actor means, means mounting said contactor means formovement relative to said switch plunger means, said contactor meansbeing in open circuit position when said spool is in said inactiveposition, means mounting said switch plunger means for movement inresponse to the initial portion of the movement of said spool frominactive position toward operating position, and means mounting saidcontactor means for movement to closed circuit position in response tosuch movement of said switch plunger means, said bypass passage beingopen during such initial portion of the movement of said spool wherebythe electric drive motor is started while the pump is undersubstantially no load.

2. In combination, a control valve comprising a hous ing having a valvespool movable axially therein from an inactive position to at least oneoperating position; a tubular member secured to said housing around anend of said spool; and spring means in said tubular member engaged withsaid spool yieldably to hold the latter in inactive position; andelectric switch means comprising a switch body including clamp meanssecuring said body on said tubular member; switch plunger means disposedadjacent said end of said spool; spring means urging said plunger meansagainst said end of said spool; a contactor on said plunger means; and acontact in said body engaged by said contactor upon movement of saidspool from inactive position.

3. The combination of claim 2 further comprising means mounting saidplunger means for movement with respect to said contactor to permitcontinued movement of said plunger means and spool following engagementof said contactor with said contact when said spool is moved in thedirection of said plunger means.

4. The combination of claim 2 wherein means are provided for arrestingmovement of said plunger means upon engagement of said contactor withsaid contact during movement of said spool in the direction away fromsaid plunger means, whereby movement of said spool to operating positionmay be continued.

5. The combination of claim 2 wherein said valve spool isaxially movablefrom an inactive position to either of two operating positions, andthere are spaced apart contacts in said body straddling said contactorand alternately contacted by the latter upon movement of said spooltoward one or the other operating positions, and there are meansmounting said plunger means for movement with respect to said contactorto permit continued movement of said plunger means and spool when saidspool is moved in the direction of said plunger means followingengagement of said contactor with one of said spaced apart contacts, andmeans are provided for arresting movement of said plunger means in theopposite direction upon engagement of said contactor with the other oneof said spaced apart contacts for continued movement of said spool awayfrom said plunger means.

6. In combination, a control valve comprising a housing having a valvespool movable axially therein from an inactive position to at least oneoperating position; a tubular member secured to said housing around anend of said spool; and spring means in said tubular member engaged withsaid spool yieldably to hold the latter in inactive position; andelectric switch means comprising a switch body including clamp meanssecuring said body on said tubular member; switch plunger means disposedadjacent said end of said spool; spring means urging said plunger meansagainst said end of said spool; a contactor on said plunger means; acontact in said body engaged by said contactor upon movement of saidspool from inactive position; and means for adjustably clamping saidbody on said tubular member to vary the space between said contactor andcontact when said spool is in inactive position.

7. The combination of claim 6 wherein said body has a transparent coverwhich encloses said contactor and contact in said body and through whichsaid contactor and contact are visible to facilitate adjustable clampingof said body on said tubular member.

8. In combination, a spool type control valve and an electric switch foruse with said control valve, said electric switch comprising a switchbody having fixed and movable jaw means defining a socket for clampingon a tubular member around one end of said valve spool; a movable switchplunger means in said body extending axially from the bottom of saidsocket for abutting engagement with said one end of said spool; acontactor means on said plunger means; and a contact in said body, saidcontactor means being operative to engage said contact upon movement ofsaid plunger means in one direction as a consequence of movement of saidspool.

9. The combination of claim 8 wherein there is a pair of spaced apartcontacts in said body straddling said contactor means, and means isprovided for causing said contactor means alternately to enagage saidcontacts upon movement of said plunger means in opposite directions as aconsequence of movement of said spool in opposite directions.

10. The combination of claim 9 wherein said body has a transparent covermeans enclosing said contactor means and contacts in said body andthrough which said contactor means and contacts are visible forfacilitating clamping of said switch with said contactor means spacedbetween said contacts.

References Cited by the Examiner UNITED STATES PATENTS 1,711,565 5/1929Hatfield et al 103-25 X 2,323,519 7/1943 Dean.

2,331,109 10/1943 De Ganahl 20061.86 X 2,399,033 4/1946 Hudson ZOO-61.862,609,665 9/1952 Rappl -60 2,718,240 9/1955 Margrave.

3,104,529 9/1963 Goss 6053 JULIUS E. WEST, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,228,193 January 11, 1966 Herbert H. Schmiel et al.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

In the grant, lines 1 and 2, for "Herbert H. Schmiel, of Willoughby,Ohio, and Louis G. Hajma, of Warrensville Heights, Ohio," read HerbertH. Schmiel, of Willoughby, Ohio, and Louis G. Ha'jma, of WarrensvilleHeights, Ohio, assignors to Parker-Hannifin Corporation, of Cleveland,Ohio,

a corporation of Ohio, line 12, for "Herbert H. Schmiel and Louis G.Hajma, their heirs" read ParkerHannifin Corporation, its successors inthe heading to the printed specification, lines 4 to 6, for "Herbert H.Schmiel, Trailard Drive, Willoughby, Ohio, and Louis G. Hajma, 24800Emery Road, Warrensville Heights, Ohio" read Herbert H. Schmiel,Willoughby, Ohio, and Louis G. Hajma, Warrensville Heights, Ohio,assignors to Parker-Hannifin Corporation, Cleveland,

Ohio, a corporation of Ohio Signed and sealed this 16th day of August1966.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner ofPatents

1. IN COMBINATION, A DIRECTIONAL CONTROL VALVE COMPRISING A HOUSING HAVING AN INLET PORT FOR CONNECTION WITH A PUMP, A TANK PORT FOR CONNECTION WITH A TANK, AND AT LEAST ONE MOTOR PORT FOR CONNECTION WITH A FLUID MOTOR, SAID HOUSING ALSO HAVING A BORE THERETHROUGH INTERSECTED AXIALLY THEREALONG BY A BYPASS PASSAGE FROM SAID INLET PORT TO SAID TANK PORT, AND A PRESSURE FEED PASSAGE FROM SAID INLET PORT TO SAID MOTOR PORT; A VALVE SPOOL MOVABLE AXIALLY IN SAID BORE FROM AN INACTIVE SPRING-HELD POSITION WHEREAT SAID INLET AND TANK PORTS ARE IN FLUID COMMUNICATION VIA SAID BYPASS PASSAGE AND COMMUNICATION BETWEEN SAID INLET AND MOTOR PORTS VIA SAID FEED PASSAGE IS BLOCKED BY SAID SPOOL, TO AN OPERATING POSITION WHEREAT SAID SPOOL CLOSES SAID BYPASSS PASSAGE AND FLUID COMMUNICATION IS ESTABLISHED THEREBY BETWEEN SAID INLET AND MOTOR PORTS VIA SAID FEED PASSAGE WHEREBY SAID FLUID MOTOR IS ACTUATED BY FLUID UNDER PRESSURE IN SAID INLET PORT CONDUCTED TO THE MOTOR THROUGH SAID MOTOR PORT; AND ELECTRIC SWITCH MEANS FOR ENERGIZING AN ELECTRIC DRIVE MOTOR FOR SAID PUMP; SAID SWITCH MEANS COMPRISING A BODY SECURED TO SAID HOUSING, A SWITCH MEANS COMPRISING A BODY SECURED AND END OF SAID SPOOL, A CONTACTOR MEANS, MEANS MOUNTING SAID CONTACTOR MEANS FOR MOVEMENT RELATIVE TO SAID SWITCH PLUNGER MEANS, SAID CONTACTOR MEANS BEING IN OPEN CIRCUIT POSITION WHEN SAID SPOOL IS IN SAID INACTIVE POSTION, MEANS MOUNTING SAID SWITCH PLUNGER MEANS FOR MOVEMENT IN RESPONSE TO THE INITIAL PORTION OF THE MOVEMENT OF SAID SPOOL FROM INACTIVE POSITION TOWARD OPERATING POSITION, AND MEANS MOUNTING SAID CONTACTOR MEANS FOR MOVEMENT TO CLOSED CIRCUIT POSITION IN RESPONSE TO SUCH MOVEMENT OF SAID SWITCH PLUNGER MEANS, SAID BYPASS PASSAGE BEING OPEN DURING SUCH INITIAL PORTION OF THE MOVEMENT OF SAID SPOOL WHEREBY THE ELECTRIC DRIVE MOTOR IS STARTED WHILE THE PUMP IS UNDER SUBSTANTIALLY NO LOAD. 